Binder element



C. E. EMMER BINDER ELEMENT Feb. 27, 1951 2 Sheets-Sheet 1 Filed NOV. 24, 1948 [I'YVE/YZUP CZar/as Ezzwma Ezrzmer 1/ 7 by Z 2,... /QM/M H2735 C. E. EMMER BINDER ELEMENT Feb. 27, 1951 2 Sheets-Sheet 2 Filed NOV. 24, 1948 patented Fe. 27, 1951 BINDER ELEMENT Charles Edward Emmer, Chicago, Ill., assignor to General Binding Corporation, Chicago, 111., a corporation of Illinois Application November 24, 1948, Serial No. 61,867

8 Claims. (Cl. 1291) This invention relates to book binders and more particularly, to an improved plastic binder element having a solid backbone with shaped fingers extending from one longitudinal side operative to recurl, after fiexing, into a preformed configuration, thereby facilitating simultaneous passage of a plurality of such fingers through a stack of perforated, aligned, loose pages as and for the binding of books, notebooks, folders, memoranda, and the like.

Heretofore, those versed in the art have formed various plastic binder elements to define a continuous back portion from which a plurality of ring fingers are extended for passage through aligned page perforations. The present invention, therefore, necessarily relates to an improved construction of a plastic binder element having the aforementioned characteristics.

A binder element constructed in accordance with my invention is first formed of thermoplastic sheet or strip material and is stamped or cut to define a solid backbone portion with backbone teeth extending from one longitudinal side and with ring fingers extending from the opposite longitudinal side of the backbone. The binder element is then preformed to define the desired shape.

In one embodiment of the present invention, the backbone and the backbone teeth define an arcuate segment and each ring finger is formed to define a loop terminating in a fiat extension at a point of merger which is carefully designed to define an arcuate segment with a definite radius. The looped fingers are overlapped by the backbone teeth and the fiat extensions of the fingers extend inwardly into the closed loop, defined by the backbone and the looped fingers, on a plane roughly corresponding to a chord segment of the closed loop. As a result, the binder element presents an unusually handsome appearance while at the same time it provides a mechanically strong and functionally efiicient binder.

The construction described has inherent engineering advantages also in that a book or journal bound with one of my binder elements may be subjected to unusually rigorous use.

For example, if a stack of pages bound with my bonder element is separated and each respective group of sheets is pulled in an opposite direction, there is a notable absence of a tendency to spread and the strength of the binding accomplished through the use of my invention is limited only to the extent of the tensile strength of the material used in the element. This ment to slide easily without interference from unnecessary protuberances in the binder loop, thereby acteristics of bound books.

Another object of my invention is to provide a binder element with overlapping backbone fingers in registered alignment with looped ringfingers.

A further object of my invention is to provide a binder element which minimizes the number of steps necessary to bind a stack of loose pages. Another object of my invention is to provide a binder element which has a simplified structure,

is economical to manufacture, and is convenientin operation.

The exact nature and other objects of my invention will appear to thos versed in the art through reference to the following detail description and the accompanying drawings in which I have shown a preferred embodiment of a binder incorporating the features of my in-- vention.

On the drawings: Figure 1 is a perspective view of a book bound with a binder element embodying the features of my invention;

Figure 2 is a cross-sectional view taken on line IIII of Figure 1;

Figure 3 is a cross-sectional view similar to the view of Figure 2 but showing the relationship of book pages to the binder element structure when the book is open;

Figure 4 is a perspective view of a binder element segment embodying the principles of my invention;

Figure 5 is a partial magnified view of the binder element shown in Figure 4 showing the ring fingers extended as for insertion into a stack of aligned, perforated, loose sheets;

Figure 6 is a plan view of a book bound with a binder element incorporating the principles of my invention but modified in certain respects;

Figure 7 is a cross-sectional view taken on line VIIVII of Figure 6;

Figure 8 is a cross-sectional view similar to the view of Figure 7 but showing the ring fingers extended as for insertion into a stack of aligned,-

perforated, loose sheets;

improving page manipulation char-- Figure 9 is a perspective view of a modified binder element segment incorporating the principles of my invention; and

Figure 10 is a cross-sectional view similar to the view of Figure 7 showing an alternative modification of the extension of the ring finger.

As shown on the drawings:

Referring to Figures 1, 2 and 3, a book or stack of loose sheets i having a plurality of aligned perforations is adjacent one edge of the stack of pages is bound together by a binder element indicated generally at ll.

The binder element H has an arcuate backbone portion is and a plurality of backbone fingers 19, also sometimes referred to herein for the sake of convenience as backbone teeth, along one longitudinal edge integral with the back, each curved to extend the are described by the back portion. Extending from the backbone IS on the opposite longitudinal edge of the backbone are a plurality of ring fingers 2G integral with the back, each curled to form a loop.

The loops defined by the ring fingers 20 are terminated in a plurality of flattened, straight, extension portions which form the free ends of the fingers. The point of termination where the fingers 2G join the free ends 23 forms an elbow having unique characteristics which will.

be disclosed in a subsequent portion of this description.

Each of the ring fingers 25 are offset as at 22 to form a plurality of loop segments 2| concentric with the ring finger loops but having a circular diameter slightly less than the diameter of the main loop.

As may be best seen in Figures 2, 3 and 4, the ring fingers 2:; turn inside and are overlapped by the backbone fingers l5. The segments 2| of the ring fingers come into registered alignment with the backbone fingers so that a perfectly smooth, fitted, circular loop is formed by the finished binder element IT.

The fiat extensions 23 extend inwardly away from the base of the backbone teeth 19 on a plane approximately defined by chords drawn to the arcuate backbone it. The extensions 23 may vary in length, but are shown in this embodiment as terminating short of contact engagement with the inside of the loop.

The binder element I? is preferably formed of a fiat sheet or strip of any resilient thermoplastic material having certain desirable characteristics, for example, the material should not be highly inflammable or explosive and it should have a high resistance to deterioration by weather and temperature. It will, of course, be understood that the principles of this invention are equally applicable to hinder elements made of metal or any other suitable material composition.

The sheet material is stamped or cut to the configuration of a comb-like binder element I! having a backbone portion IS with a plurality of backbone teeth 1 9 and a plurality of ring fingers 20 extending in opposite direction from the backbone portion. The material is then suitably molded, shaped or curled in the usual manner to take the shape illustrated in the drawings and referred to above.

Referring now to Figures 6 through 10, a modified binder element Ila is shown binding a book or a sheaf of pages 2 3 having a plurality of aligned perforate holes 25 lying adjacent to one edge.

The binder element Ila is similar in character to the binder element 1'. previously described with the exception that the original plastic heet material is preforin d to define a flat backbone portion E8a having a plurality of curved backbone teeth ia integral therewith. Extending from the back in direction opposite to the backbone teeth are a plurality of ring fingers 29a offset as at 22a to form segments Zia and terminating in the free ends formed by the fiat extensions 2 The extensions 23a forming the e ends of the ring fingers lie in any internal loop plane and are not necessarily in a plane parallel to the fiat backbone 52a. The extensions 23a may be of varying lengths as is illustrated. by the long version shown in Figure 7 and short version shown in Figure 16.

It should also be noted that tl-e backbone teeth lSa are shown in Figures 6 and 9 as being of substantially smaller width than the ring segments 25a. This feature is especially desirable since it affords a dimensional tolerance in the registration of longitudinal alignment between the rin finger segments Zia and the backbone fingers 28a.

To insert the binder element i? or l'la into a book or other stack of loose leaf material to be bound, the element is spread to assume the shape shown in Figure 8. It will be apparent that the process of spreading consists of uncurling the ring fingers 26 or 253a. Wltl'lll'l their elastic limits. "Spreading be conveniently accomplished with any of the usual mechanical devices now common to the art.

When the binder element is spread to its uncurled position, the extensions 23 or 23a lie fully exposed and readily receive the plurality of aligned perforated sheets or pages. is may be seen on Figure 8, the successive positions of a representative stack of pages 2 3 are shown in dotted lines as they are fitted onto a binder element.

Thereafter, the ring fingers 29 or 26a are permitted to recurl under their own resiliency and, in recurling, take the positions shown in figures 2 and 10 with the backbone teeth or lying in aligned overlapping engagement with the ring finger segments 2! or 2 la and the flat extensions 23 or 23a projecting inwardly into the ring finger loop.

Attention is drawn to the fact that the fiat extensions of the looped ring fingers are in spaced relationship to the backbone of the binder element and require no treatment with solvents or adhesives of any kind to complete the binder structure.

The operative constructional features of my binder element are aptly illustrated in Figure 3 where a book bound with a binder element l? constructed in accordance with the present invention is shown in an open position. It should be noted that the right-hand group of prges is retained by the ring finger 2-3 and the left-hand group of pages is positioned substantially in alignment with the ring finger segments 2!. If the respective groups of pages of an open book were subjected to oppositely directed pulling forces, a stress condition corres ending to the most rigorous type of book use imaginable would be simulated. It will be noted that under such conditions, the left-hand group of pages bears against the ring finger segments 2! urging the segments in engagement with the backbone fingers [9.

It is a well-known physical phenomenon that two objects held in surface contact and subjected to a small amount of force applied perpendicularly are capable of resisting a very high separating force applied laterally. In a ring binder element constructed in accordance with the present invention, this phenomenon is utilized because of the peculiar shape and location of the comparatively rigid backbone teeth it.

When the ring finger segments 2! engage these teeth, a comparatively large surface area is effectively contacted, thus, the perpendicular restraining force due to the inherentrigidity of the backbone teeth plus the perpendicular component of the separating force applied to a selected group of pages of the bound book is capable of successfully resisting the proportionately greater forces tending to separate the teeth and the fingers of the binder element.

Thus, it will be immediately evident to anyone applying a test of the character described that it is virtually impossible to spread the binder elements ll or Ila under usage conditions to which bound books are normally subjected.

Attention is further drawn to the fact that the segments 2i and Zia are offset at their point of contact with the backbone teeth 59 and 92a. As may best be seen on Figure 3, this feature permits book pages to freely slide throughout the limits of the ring finger loop thereby facilitating the manipulation of book pages from the closed to the open position.

One more additional feature of note in the present invention is the peculiar shape or" the ring finger at the point where the segment 2! or 21a merges with the extension or 23a. As may best be seen on Figures 8, 9 and 10, this portion of the ring finger defines an elbow 25a which takes the form of an arc segment of a circle of definite radius. The purpose of this particular form is to permit sheets to slide onto the ring finger loop with great facility during the binding operation (Figure 8).

It will be evident to those skilled in the art that I have described a binder element structure which marks a notable advance in the book binding art. While I have resorted. to details for the purpose of properly explaining my invention, it is to be understood that my invention is not limited to the precise structure shown and described in the present preferred embodiment, the same being merely illustrative of the principles of my invention.

I claim as my invention:

1. A binder element for insertion into a stack of sheets having a plurality of aligned perfora-' tions adjacent one edge thereof, said binder element formed oi an integral resilient sheet of material comprising a backbone, a plurality of arcuate teeth extending from one longitudinal edge of said backbone, and a plurality of fingers extending from the opposite edge thereof and aligned with said teeth, said fingers being curled to form closed loops with said backbone, said fingers having a segment seating on the inner face of said arcuate teeth in conforming frictional contact and having an inturned straight free end portion joined to said segment by an elbow, whereby forces acting on said stack of sheets to spread the binder are checked by an initially increasing frictional resistance between said teeth and said segments and whereby when excessive forces have spread the binder said free end portions inturned at said elbows retain said stack of sheets on said fingers.

2. A binder element for insertion into a stack of sheets having a plurality of aligned perforations adjacent one edge thereof, said binder element formed of an integral resilient sheet of material comprising a backbone, a plurality of arcuate teeth extending from one longitudinal edge of said backbone, and a plurality of fingers extending from the opposite edge thereof and aligned with said teeth, said fingers being curled to form closed loops with said backbone, said fingers having a segment seating on the inner face of said arcuate teeth in conforming frictional contact and having an inturned straight free end portion joined to said segment by an elbow, whereby forces acting on said stack of sheets to spread the binder are checked by an initially increasing frictional resistance between said teeth and said segments and whereby when excessive forces have spread the binder said free end portions inturned at said elbows retain said stack of sheets on said fingers, and said teeth being of narrower width than said fingers to afford increased tolerance in longitudinal registration.

3. A binder element for insertion into a stack of sheets having a plurality of aligned perforations adjacent one edge thereof, said binder element formed of an integral resilient sheet of material comprising a backbone, a plurality of arcuate teeth extending from one longitudinal edge of said backbone, and a plurality of fingers extending from the opposite edge thereof and aligned with said teeth, said fingers being curled to form closed loops with said backbone, said fingers having a segment offset inwardly by the thickness of said teeth and seating on the inner face of said arcuate teeth in conforming frictionalcontact and having an inturned straight free end portion joined to said segment by an elbow, whereby forces acting on said stack of sheets to spread the binder ar checked by an initially increasing frictional resistance between said teeth and said segments and whereby when excessive forces have spread the binder said free end portions inturned at said elbows retain said stack of sheets on said fingers.

4. A binder element for insertion into a stack of sheets having a plurality of aligned perforations adjacent one edge thereof, said binder element formed of an integral resilient sheet of material comprising an arcuate backbone, a plurality of arcuate teeth extending from one longitudinal edge of said backbone, and a plurality of fingers extending from the opposite edge thereof and aligned with said teeth, said fingers being curled to form closed loops with said backbone, said fingers having a segment seating on the inner face of said arcuate teeth in conforming frictional contact and having an inturned straight free end portion joined to said segment by an elbow, whereby forces acting on said stack of sheets to spread the binder are checked by an initially increasing frictional resistance between said teeth and said segments and whereby when excessive forces have spread the binder said free end portions inturned at said elbows retain said stack of sheets on said fingers.

5. A binder element for insertion into a stack of sheets having a plurality of aligned perforations adjacent one edge thereof, said binder element formed of an integral resilient sheet of material comprising an arcuate backbone, a plurality of arcuate teeth extending from one longitudinal edge of said backbone,-and a. plurality of fingers extending from the opposite edge thereof and aligned with said teeth, said fingers being curled to form closed loops with said backbone,

said fingers having a segment seating on the inner face of said arcuate teeth in conforming frictional contact and having an inturned straight free end portion joined to said segment by an elbow, whereby forces acting on said stack of sheets to spread the binder are checked by an ini tially increasing frictional resistance between said teeth and said segments and whereby when excessive forces have spread the binder said free end portions inturned at said c bows retain said stack of sheets on said fingers, and said teeth being of narrower Width than said fingers to a1"- ford increased tolerance in longitudinal registration.

6. A binder element for insertion into a stack of sheets having a plurality of aligned perforations adjacent one edge thereof, said binder element formed of an integral resilient sheet of material comprising an arcuate backbone, a plurality of arcuate teeth extending from one longitudinal edge of said backbone, and pl fingers extending from the opposite edge thereof and aligned with teeth, said fingers being curled to form closed loops with said ba :bone, said fingers having a segment oifset inwardly the thickness of said teeth and seating on the inner face of said arcuate teeth in conforming frictional contact and having an inturned straight free end portion joined to said segment by an elbow, whereby forces acting on said stack: of sheets to spread the binder are checked by an initially increasing frictional resistance between said teeth and said segments and whereby when excessive forces have spread the binder said free end portions inturned at said elbows retain said stack of sheets on said fingers.

7. A binder element for insertion into a stack of sheets having a plurality of aligned perforations adjacent one edge thereof, said binder element formed of an integral resilient sheet of 1nateria] comprising a flat backbone, a plurality of arcute teeth extending from one longitudinal edge of said backbone, and a plurality of fingers extending from the opposite edge thereof and aligned with said teeth, said fingers being curled to form closed loops with said backbone, said fingers having a segment seating on the inner face of said .arcuate teeth in conforming frictional contact and having an inturned straight free end portion joined to said segment by an elbow, whereby forces acting on said stack of sheets to spread the binder are checked by an initially increasing frictional resistanc between said teeth and said segments and whereby when excessive forces have spread the binder said free end portions inturned at said elbows retain said stack of sheets on said fingers.

8. A binder element for insertion into a stack of sheets having a plurality of aligned perforations adjacent one edge thereof, said binder element formed of an integral resilient sheet of material comprising a flat backbone, a plurality of arcuate teeth extending from one longitudinal edge of said backbone, and a plurality of fingers extending from the opposite edge thereof and aligned with said teeth, said fingers being curled to form closed loops with said backbone, said fingers having a segment seating on the inner face of said arcuate teeth in conforming frictional contact and having an inturned straight free end portion joined to said segment by an elbow, and relieved from said backbone, whereby forces acting on said stack of sheets to spread the binder are checked by an initially increasing frictional resistance between said teeth and said segments and whereby when excessive forces have pread the binder said free end portions inturned at said elbows retain said stack of sheets on said fingers.

CHARLES EDWARD EMMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,176,314 Russell Oct. 17, 1939 2,246,702 Stewart June 24, 1941 2,251,3 l3 Spinner Aug. 5, 1941 2,277,834 Spinner Mar. 31, 1942 2,407,656 Emmer Sept. 17, 1946 

